System, a lithographic apparatus, and a method for reducing oxidation or removing oxide on a substrate support

Abstract

A system including: a substrate support configured to hold a substrate; a conductive or semi-conductive element contacting the substrate support and covering at least part of the substrate support; and a charging device configured to apply a positive potential to the conductive or semi-conductive element with respect to the part of the substrate support that is covered by the conductive or semi-conductive element.

The invention claimed is: 
     
       1. A system comprising:
 a substrate support configured to hold a substrate, the substrate support comprising one or more openings configured to exhaust gas so as to clamp the substrate to the substrate support; 
 a conductive or semi-conductive element contacting, or configured to contact, the substrate support and covering, or configured to cover, at least part of the substrate support; and 
 a charging device configured to apply a positive potential to the conductive or semi-conductive element with respect to the part of the substrate support that is covered by the conductive or semi-conductive element. 
 
     
     
       2. The system of  claim 1 , wherein the substrate support has a main body and a plurality of burls projecting from a main body surface of the main body, each burl having a terminal end surface configured to contact a surface of a substrate to support the substrate, and
 wherein the charging device is configured to apply the positive potential to the conductive or semi-conductive element with respect to the terminal end surfaces of the plurality of burls of the substrate support. 
 
     
     
       3. The system of  claim 1 , wherein the positive potential is a continuous voltage in the range from 0.1V to 10V. 
     
     
       4. The system of  claim 1 , wherein the substrate support is electrically grounded and a positive potential is applied to the conductive or semi-conductive element, or
 wherein the conductive or semi-conductive element is electrically grounded and a negative potential is applied to the substrate support. 
 
     
     
       5. The system of  claim 1 , comprising an electrolyte, wherein the electrolyte at least partially fills a space between the substrate support and the conductive or semi-conductive element. 
     
     
       6. The system of  claim 5 , further comprising an electrolyte supply device configured to at least partially fill the space with the electrolyte. 
     
     
       7. The system of  claim 1 , further comprising a thermal conditioning device configured to thermally condition the conductive or semi-conductive element such that an electrolyte condenses on the conductive or semi-conductive element. 
     
     
       8. The system of  claim 1 , wherein the charging device is configured to apply the positive potential: only during loading and unloading of a substrate on the substrate support, and/or only during cleaning of the substrate support. 
     
     
       9. The system of  claim 1 , wherein the charging device comprises an electrical power supply embedded in the conductive or semi-conductive element, or
 wherein the charging device comprises an electrical power supply configured to apply the positive potential to the conductive or semi-conductive element via actuatable pins each projecting through a hole in the substrate support, or 
 wherein the charging device comprises an electrical power supply configured to apply the positive potential to the conductive or semi-conductive element via a liquid confinement structure for confining a liquid on a substrate held by the substrate support, or 
 wherein the charging device comprises an air shower and an ionizer and is configured to direct an ionized air flow over the conductive or semi-conductive element. 
 
     
     
       10. The system of  claim 1 , wherein the conductive or semi-conductive element comprises any one selected from:
 a substrate held by the substrate support, the substrate comprising a photoresist for development of a pattern therein, 
 a dummy substrate held by the substrate support, 
 a metal layer applied to a main body surface of the substrate support from which a plurality of burls project, or 
 a treatment tool for mechanically cleaning the substrate support. 
 
     
     
       11. A lithographic apparatus comprising:
 a substrate table that comprises a substrate support configured to hold a substrate, the substrate support comprising one or more openings configured to exhaust gas so as to clamp the substrate to the substrate support, 
 a loading device configured to load a conductive or semi-conductive element onto the substrate support, so that the conductive or semi-conductive element contacts the substrate support and covers at least part of the substrate support, and 
 a charging device configured to apply a positive potential to a conductive or semi-conductive element contacted by the substrate support with respect to the part of the substrate support that is covered by the conductive or semi-conductive element. 
 
     
     
       12. The lithographic apparatus of  claim 11 , further comprising a projection system configured to project a patterned radiation beam onto the conductive or semi-conductive element. 
     
     
       13. The lithographic apparatus of  claim 11 , wherein the charging device is configured to operate: periodically, and/or at a specific time or at specific times during a substrate processing cycle of the lithographic apparatus, and/or at a frequency less than the frequency of substrate processing. 
     
     
       14. A method for reducing oxidation or removing oxide on a substrate support, the method comprising:
 exhausting gas through one or more openings of the substrate support so as to clamp the substrate to the substrate support; 
 contacting the substrate support with a conductive or semi-conductive element such that at least part of the substrate support is covered by the conductive or semi-conductive element, and 
 applying a positive potential to the conductive or semi-conductive element with respect to the part of the substrate support that is covered by the conductive or semi-conductive element. 
 
     
     
       15. The method of  claim 14 , further comprising:
 at least partially filling a space between the substrate support and the conductive or semi-conductive element with an electrolyte, and/or 
 thermally conditioning the conductive or semi-conductive element so that an electrolyte condenses on the conductive or semi-conductive element. 
 
     
     
       16. The method of  claim 14 , wherein the positive potential is a continuous voltage in the range from 0.1V to 10V. 
     
     
       17. The method of  claim 14 , wherein an electrolyte at least partially fills a space between the substrate support and the conductive or semi-conductive element. 
     
     
       18. The lithographic apparatus of  claim 11 , wherein the positive potential is a continuous voltage in the range from 0.1V to 10V. 
     
     
       19. The lithographic apparatus of  claim 11 , wherein the substrate support is electrically grounded and a positive potential is applied to the conductive or semi-conductive element, or
 wherein the conductive or semi-conductive element is electrically grounded and a negative potential is applied to the substrate support. 
 
     
     
       20. The lithographic apparatus of  claim 11 , comprising an electrolyte, wherein the electrolyte at least partially fills a space between the substrate support and the conductive or semi-conductive element and/or an electrolyte supply device configured to at least partially fill the space with the electrolyte. 
     
     
       21. A system comprising:
 a substrate support configured to hold a substrate; 
 a conductive or semi-conductive element contacting, or configured to contact, the substrate support and covering, or configured to cover, at least part of the substrate support; 
 an electrolyte that at least partially fill a space between the substrate support and the conductive or semi-conductive element; and 
 a charging device configured to apply a positive potential to the conductive or semi-conductive element with respect to the part of the substrate support that is covered by the conductive or semi-conductive element.